The DI818 is a high-performance digital input module within the ABB Ability™ System 800xA® hardware platform, designed specifically for industrial automation control systems. This module operates on a 24V DC power supply, supports current sinking inputs, and features 32 independent input channels, making it suitable for a wide range of industrial field signal acquisition tasks. It boasts a compact design, high reliability, excellent noise immunity, and diagnostic functions. It is widely applicable in process control, discrete manufacturing, energy management, marine, and heavy machinery sectors.
The DI818 module employs a dual-group isolation design, with 16 channels per group, and is equipped with an independent process voltage monitoring input for each group. It can promptly issue error signals in case of voltage anomalies, enhancing system reliability and maintenance efficiency. Furthermore, the module supports configurable digital filtering, effectively suppressing on-site noise and ensuring signal acquisition stability and accuracy.
2. Key Features and Benefits
| Feature Category | Detailed Description |
| Channel Configuration | 32 channels of 24V DC input, divided into two independently isolated groups of 16 channels each. |
| Voltage Supervision | One process voltage supervision input per group; provides error signal if voltage is lost. |
| Signal Filtering | Selectable digital filter times: 2 ms, 4 ms, 8 ms, 16 ms. |
| Isolation Design | Group-to-group isolation; isolation voltage of 50 V (RIV) between each group and ground. |
| Diagnostics | Module Fault, Run, and Warning indicators; individual channel status LEDs. |
| Compatibility | For use with the S800 I/O system; compatible with three Module Termination Unit (MTU) types: TU818, TU819, TU830. |
| Environmental Suitability | Operating temperature: 0 to 55°C; Storage temperature: -40 to 70°C; Protection class: IP20. |
3. Functional Details
1. Channel Structure and Isolation Design
The 32 inputs of the DI818 are divided into two electrically isolated groups of 16 channels each. This design effectively prevents ground loop interference and voltage crosstalk, enhancing system reliability in complex industrial environments. Each group has a dedicated process voltage supervision input. If a power supply anomaly is detected, an error can be reported via the ModuleBus, facilitating rapid fault location.
2. Signal Filtering and Noise Suppression
The module features built-in programmable digital filters. Users can select filter times of 2 ms, 4 ms, 8 ms, or 16 ms based on on-site interference conditions. This function effectively filters out short-duration pulse noise, ensuring accurate acquisition of valid signals longer than the set threshold.
3. Diagnostics and Status Indication
The front panel is equipped with multi-color LED indicators:
RUN (Run): Illuminates steadily when the module is operating normally.
FAULT (Fault): Illuminates when a module or channel error occurs.
WARNING (Warning): Illuminates for non-critical issues such as voltage supervision anomalies.
Additionally, each channel has an individual LED indicating the input state ("0" or "1"), aiding in on-site commissioning and maintenance.
4. Flexible Field Wiring
The module supports three types of Module Termination Units (MTUs):
TU830: Extended type, suitable for high-density wiring.
TU818: Compact type, supports single-wire connection to sensors.
TU819: Compact type, equipped with dual D-sub 25-pin connectors for standard industrial interfaces.
Users can select the appropriate MTU based on field wiring requirements, enhancing installation flexibility.
4. Application Areas
The DI818 is suitable for various industrial automation scenarios, including but not limited to:
Process Industries: Chemicals, oil & gas, water treatment.
Discrete Manufacturing: Automotive assembly, semiconductor production, packaging machinery.
Energy Management: Power monitoring, wind power, photovoltaic systems.
Marine & Offshore: Propulsion control, cabin monitoring, navigation systems.
Infrastructure: Building automation, traffic control systems.
5. Installation and Integration Notes
The DI818 module plugs directly into an S800 I/O rack and communicates with the controller via the ModuleBus. Field signals are connected through the chosen MTU. Refer to the Process Connector Pinning Table (Table 56) for wiring details. Installation considerations include:
The module should be mounted vertically to ensure proper heat dissipation.
The use of the Extended MTU (TU830) is recommended when ambient temperature exceeds 40°C.
Grounding must comply with IEC 61140 Class I requirements.
